1. Field of the Invention
The present invention relates to kites and more particularly, a novel kite module that can be flown alone or, in combination with other similar models can be assembled into a complex kite configuration. Both the basic kite and the complex combination kite are easy to fly and are controllable and stable in flight. These favorable flying characteristics are a result of the unique sructure of the kite. The basic kite of the present invention has two aerodynamic surfaces or sails, each sail arched about the same common longitudinal kite axis and each sail opening concave downward.
2. The Prior Art
U.S. Pat. No. 2,737,360 to Allison shows a kite whose sail has a generally cylindrical or conical shape with its axis running longitudinally of the kite and presenting a concave surface downwardly. The Allison kite differs from the present invention both structurally and functionally. The Allison kite typifies a class known as flexible kites, which are flexible in the lateral direction but stiff in the longitudinal direction. The longitudinal stiffness is provided in such kites by longerons, and there are no laterally extending structural members. Such kites are usually attached by the flying string to bridle strings which attach to the kite at laterally opposed points, thereby permitting the kite structure to pivot freely about a lateral axis.
The Allison kite has no fixed shape but assumes a shape depending on the strength of the wind. When there is little wind, the kite assumes a shape which is laterally narrow and flies at a higher angle of attack. When the wind is strong, the Allison kite billows out laterally and flies at a shallow angle of attack. The Allison kite changes its shape in response to gusts having a lateral component so as to maintain stability.
The Allison kite experiences some difficulty in gusty air. It is not unusual for gusts to cause the flexible kite to lose its billowed form or to collapse locally at its leading edge. Severe reverse gusts have caused such kites to turn inside out. In U.S. Pat. No. 3,767,145, Holland shows a simple improvement on the Allison kite which remedies some of the defects. Holland uses longerons which are bowed laterally so that their concave sides are facing each other. This causes the surface of the Holland kite to assume a compound curvature when in flight, which accounts for its different aerodynamic properties.
The Holland kite, like the Allison kite, differs both structurally and functionally from the kite of the present invention. The kite of the present invention is not a flexible kite in the accepted usage of that word. The shape of the sail is maintained by a curved rigid structural member located at the leading edge of each sail, and the kite of the present invention does not billow in any direction including laterally. Its shape is not dependent on the wind velocity. Further, the kite of the present invention lends itself more readily than the flexible kite to the formation of multiple kite structures.